Methods and systems for the rapid detection of concealed objects

Abstract

The present invention provides for an improved scanning process having a first stage to rapidly identify a threat location and a second stage to accurately identify the nature of the threat. The improved scanning process maintains a high degree of accuracy while still providing an operationally desirable high throughput. The present invention also uses improved processing techniques that enable the substantially automated detection of threats and decrease the dependence on operator accuracy. One embodiment of the present invention provides an apparatus for identifying an object concealed within a container. It comprises a first stage inspection system having at least two X-ray projection systems to generate a first set of data and a plurality of processors in data communication with the first stage inspection system. The processors process the first set of data to generate at least two images. The two images are used to identify at least one target region from the two images. A second stage inspection system is then used to generate an inspection region which is then positioned relative to the target region and made to at least partially physically coincide with the target region. A second set of data is produced specifically from the inspection region, data which have a high degree of specificity for the material in the inspection region.

1 . An apparatus for identifying an object concealed within a container, comprising: 
 a first stage inspection system having at least two X-ray projection systems to generate a first set of data;    a plurality of processors in data communication with the first stage inspection system wherein the processors process said first set of data to generate at least two images;    a means for identifying at least one target region from the two images;    a means for positioning an inspection region relative to the target region wherein the inspection region at least partially physically coincides with the target region; and    a second stage inspection system for generating the inspection region wherein the second stage inspection system produces a second set of data having an X-ray signature characteristic of the material in said inspection region.    
   
   
       2 . The apparatus of  claim 1  wherein said object is a threat.  
   
   
       3 . The apparatus of  claim 2  wherein said threat is at least one of an illegal drug, an explosive material, or a weapon.  
   
   
       4 . The apparatus of  claim 1  wherein the means for identifying at least one target region comprises an operator selecting a region associated with each of the images.  
   
   
       5 . The apparatus of  claim 4  wherein the operator selects a region based upon an X-ray image characteristic.  
   
   
       6 . The apparatus of  claim 5  wherein the X-ray image characteristic is at least one of mass, degree of attenuation, area, atomic number, size, shape, pattern, or context.  
   
   
       7 . The apparatus of  claim 5  wherein the operator identifies a region in a first image as likely to be the same, or closely located to it, in a second image.  
   
   
       8 . The apparatus of  claim 1  wherein the means for identifying at least one target region comprises a processor executing an algorithm to select a region associated with the images.  
   
   
       9 . The apparatus of  claim 8  wherein the region associated with the images is selected based upon an X-ray image characteristic.  
   
   
       10 . The apparatus of  claim 9  wherein the X-ray image characteristic is at least one of mass, degree of attenuation, area, atomic number, size, shape, pattern, or context.  
   
   
       11 . The apparatus of  claim 1  wherein a plurality of X-ray beam projections from the X-ray projection systems intersects the target region at an intersection area, said target region having a location.  
   
   
       12 . The apparatus of  claim 11  wherein the location of the target region is determined by identifying a set of coordinates for the intersection area.  
   
   
       13 . The apparatus of  claim 12  wherein a plurality of control commands is produced in response to the determination of said location of the target region.  
   
   
       14 . The apparatus of  claim 12  wherein the inspection region is positioned relative to the target region in response to the plurality of control commands using a three-axis control system.  
   
   
       15 . The apparatus of  claim 1  wherein the means for positioning said inspection region relative to the target region includes a plurality of adjustable apertures.  
   
   
       16 . The apparatus of  claim 15  wherein the apertures can be physically moved in the direction of the main beam axis.  
   
   
       17 . The apparatus of  claim 16  wherein the aperture is a ring aperture having an adjustable diameter.  
   
   
       18 . The apparatus of  claim 1  wherein the means for positioning said inspection region relative to the target region comprises a conveyor operable to move in elevation relative to the second stage inspection system.  
   
   
       19 . The apparatus of  claim 1  wherein the means for positioning said inspection region relative to the target region comprises an aperture and ring aperture.  
   
   
       20 . The apparatus of  claim 1  wherein the second stage inspection system comprises an inspection region generation system.  
   
   
       21 . The apparatus of  claim 20  wherein the inspection region generation system comprises a source of X-ray radiation.  
   
   
       22 . The apparatus of  claim 21  wherein the inspection region generation system comprises an energy dispersive detector.  
   
   
       23 . The apparatus of  claim 20  wherein the inspection region generation system comprises an array of transmission detectors.  
   
   
       24 . The apparatus of  claim 20  wherein the inspection region generation system comprises an energy dispersive detector and an array of transmission detectors.  
   
   
       25 . The apparatus of  claim 24  wherein the energy dispersive detector is used to produce a signature of the material in the inspection region and the array of transmission detectors is used to produce data defining at least one of mass, degree of attenuation, area, average atomic number, of the material in a beampath.  
   
   
       26 . The apparatus of  claim 23  or  24  wherein the array of transmission detectors is in a ring formation.  
   
   
       27 . The apparatus of  claim 24  wherein the array of transmission detectors comprises high energy and low energy detectors.  
   
   
       28 . The apparatus of  claim 27  wherein data generated from the transmission detectors is used to identify a reference spectrum.  
   
   
       29 . The apparatus of  claim 28  wherein said identification of a reference spectrum is achieved by identifying a spectrum associated with data generated from both the high energy detectors and the low energy detectors.  
   
   
       30 . The apparatus of claims  27 ,  28  or  29  wherein said second set of data comprises high energy and low energy transmission data characteristic of the X-ray properties of the material in a beampath.  
   
   
       31 . The apparatus of  claim 28  wherein the reference spectrum is used to correct a diffraction spectrum.  
   
   
       32 . The apparatus of  claim 28  wherein the reference spectrum is used to correct for beam hardening.  
   
   
       33 . The apparatus of  claim 23  wherein data generated from the transmission detectors is used to identify a boundary of the container.  
   
   
       34 . The apparatus of  claim 23  wherein data generated from the transmission detectors is used to generate an image.  
   
   
       35 . The apparatus of  claim 1  wherein the X-ray signature characteristic is a diffraction pattern.  
   
   
       36 . The apparatus of  claim 1  wherein the X-ray signature characteristic is a scatter spectrum.  
   
   
       37 . The apparatus of  claim 1  wherein the X-ray signature characteristic is an electronic response signal.  
   
   
       38 . The apparatus of  claim 1  further comprising a processor in data communication with at least one of the first stage inspection system or the second stage inspection system wherein the processor is capable of executing a neural network to process at least one of the first set of data or the second set of data to determine the existence of a threat.  
   
   
       39 . The apparatus of  claim 38  wherein the neural network operates as a back-propagation network having a plurality of nodes and wherein said nodes are organized in a series of successive layers, each layer comprising at least one node that receives inputs from nodes in a prior layer and transmits outputs to nodes in a subsequent layer.  
   
   
       40 . The apparatus of  claim 39  wherein nodes in a first layer are weighted in accordance with their distance from at least one node in a second layer.  
   
   
       41 . The apparatus of  claim 38  wherein the neural network is trained to determine the existence of the threat using a library of known threats.  
   
   
       42 . The apparatus of  claim 1  wherein the inspection region encompasses portions of the container, volume within the container and volume external to the container and wherein a composite signal is produced when the portions of the container, volume within the container and volume external to the container are exposed to said X-ray beams.  
   
   
       43 . The apparatus of  claim 42  further comprising a processor to correct the composite signal by substantially removing a signal produced by exposing the volume external to the container to said X-ray beams.  
   
   
       44 . The apparatus of  claim 43  wherein the volume external to the container includes air.  
   
   
       45 . The apparatus of  claim 43  wherein the volume external to the container includes metal.  
   
   
       46 . The apparatus of  claim 43  wherein said correction of the composite signal includes correcting for a plurality of attenuation affects caused by exposing the volume external to the container to said X-ray beams.  
   
   
       47 . The apparatus of  claim 46  wherein one of said attenuation affects is beam hardening.  
   
   
       48 . The apparatus of  claim 1  wherein the second set of data comprises a composite signal produced when at least two of the container, volume within the container, or volume external to the container are exposed to said X-ray beams.  
   
   
       49 . The apparatus of  claim 1  wherein the second stage inspection system comprises at least two energy dispersive detectors.  
   
   
       50 . The apparatus of  claim 49  wherein the energy dispersive detectors are separated by a plurality of vanes.  
   
   
       51 . The apparatus of  claim 50  further comprising four energy dispersive detectors.  
   
   
       52 . The apparatus of  claim 51  wherein the energy dispersive detectors are arranged into four quadrants.  
   
   
       53 . A method for identifying an object concealed within a container, comprising: 
 generating a first set of data using a first stage inspection system having at least two X-ray projection systems;    processing said first set of data to generate at least two images using a plurality of processors in data communication with the first stage inspection system;    identifying at least one target region from the two images;    positioning an inspection region relative to the target region wherein the inspection region at least partially physically coincides with the target region;    generating the inspection region through a second stage inspection system; and    producing a second set of data having a X-ray signature characteristic of the material in the inspection region.    
   
   
       54 . The method of  claim 53  wherein an operator identifies at least one target region by selecting a region associated with the images, said region being selected based upon an X-ray image characteristic.  
   
   
       55 . The method of  claim 54  wherein the X-ray image characteristic is at least one of mass, degree of attenuation, total area, atomic number, size, shape, or organic to inorganic ratio.  
   
   
       56 . The method of  claim 53  wherein an operator identifies at least two target regions by selecting regions associated with each of said images.  
   
   
       57 . The method of  claim 56  wherein the operator identifies a region in a first image as being similar to a region in a second image.  
   
   
       58 . The method of  claim 57  wherein the operator identifies the regions as being similar based upon at least one of mass, degree of attenuation, total area, atomic number, size, shape, or organic to inorganic ratio.  
   
   
       59 . The method of  claim 53  wherein the at least one target region is identified by a processor executing an algorithm to select a region associated with the images.  
   
   
       60 . The method of  claim 59  wherein the region associated with the images is selected based upon an X-ray image characteristic.  
   
   
       61 . The method of  claim 60  wherein the X-ray image characteristic is at least one of mass, degree of attenuation, total area, atomic number, size, shape, or organic to inorganic ratio.  
   
   
       62 . The method of  claim 53  wherein the at least one target region is identified by a processor executing an algorithm to select at least two regions associated with each of said images.  
   
   
       63 . The method of  claim 62  wherein the processor identifies a region in a first image as being similar to a region in a second image.  
   
   
       64 . The method of  claim 63  wherein the processor identifies the regions as being similar based upon at least one of mass, degree of attenuation, total area, atomic number, size, shape, or organic to inorganic ratio.  
   
   
       65 . The method of  claim 53  wherein a plurality of X-ray beam projections from the X-ray projection systems intersect the target region at an intersection area, said target region having a location.  
   
   
       66 . The method of  claim 65  wherein the location of the target region is determined by identifying a set of coordinates for the intersection area.  
   
   
       67 . The method of  claim 66  wherein a plurality of control commands is produced in response to the determination of said location of the target region.  
   
   
       68 . The method of  claim 67  wherein the inspection region is positioned relative to the target region in response to the plurality of control commands using a three-axis control system.  
   
   
       69 . The method of  claim 53  wherein the positioning of the inspection region relative to the target region is achieved using a plurality of adjustable apertures.  
   
   
       70 . The method of  claim 69  wherein the aperture can be physically moved horizontally or vertically.  
   
   
       71 . The method of  claim 69  wherein the aperture is a ring aperture having an adjustable diameter.  
   
   
       72 . The method of  claim 53  wherein the positioning of the inspection region relative to the target region is achieved using a conveyor operable to move in elevation relative to the second stage inspection system.  
   
   
       73 . The method of  claim 53  wherein the positioning of the inspection region relative to the target region is achieved using an aperture and ring aperture.  
   
   
       74 . The method of  claim 53  wherein the second stage inspection system comprises an energy dispersive detector.  
   
   
       75 . The method of  claim 53  wherein the second stage inspection system comprises an array of transmission detectors.  
   
   
       76 . The method of  claim 53  wherein the second stage inspection system comprises an energy dispersive detector and an array of transmission detectors.  
   
   
       77 . The method of  claim 76  wherein the energy dispersive detector is used to produce a signature of the material in the inspection region and the array of transmission detectors is used to produce data defining at least one of mass, degree of attenuation, area, average atomic number, of the material in a beampath.  
   
   
       78 . The method of  claim 75  or  76  wherein the array of transmission detectors is in a ring formation.  
   
   
       79 . The method of  claim 75  wherein the array of transmission detectors comprises high energy and low energy detectors.  
   
   
       80 . The method of  claim 79  wherein a reference spectrum is determined by identifying a spectrum associated with data generated from both the high energy detectors and the low energy detectors.  
   
   
       81 . The method of  claim 80  wherein the reference spectrum is used to correct a diffraction spectrum.  
   
   
       82 . The method of  claim 80  wherein the reference spectrum is used to correct for beam hardening.  
   
   
       83 . The method of  claim 75  wherein data generated from the transmission detectors is used to identify a boundary of the container.  
   
   
       84 . The method of  claim 53  wherein the X-ray signature characteristic is a diffraction pattern.  
   
   
       85 . The method of  claim 53  wherein the X-ray signature characteristic is a scatter spectrum.  
   
   
       86 . The method of  claim 53  wherein the X-ray signature characteristic is an electronic response signal.  
   
   
       87 . The method of  claim 53  further comprising the step of executing a neural network to process at least one of the first set of data or the second set of data to determine the existence of a threat.  
   
   
       88 . The method of  claim 87  wherein the neural network operates as a back-propagation network having a plurality of nodes and wherein said nodes are organized in a series of successive layers, each layer comprising at least one node that receives inputs from nodes in a prior layer and transmits outputs to nodes in a subsequent layer.  
   
   
       89 . The method of  claim 88  wherein nodes in a first layer are weighted in accordance with their distance from at least one node in a second layer.  
   
   
       90 . The method of  claim 87  wherein the neural network is trained to determine the existence of the threat using a plurality of libraries.  
   
   
       91 . The method of  claim 90  wherein the plurality of libraries are accessible via a network.  
   
   
       92 . The method of  claim 91  wherein the plurality of libraries comprise at least one library of threats and at least one library non-threats.  
   
   
       93 . The method of  claim 92  wherein the plurality of libraries further comprises at least one buffer library.  
   
   
       94 . The method of  claim 53  wherein the second stage inspection system comprises at least two energy dispersive detectors.  
   
   
       95 . The method of  claim 94  wherein the energy dispersive detectors are separated by a plurality of vanes.  
   
   
       96 . The method of  claim 53  wherein the second stage inspection system comprises four energy dispersive detectors.  
   
   
       97 . The method of  claim 96  wherein the energy dispersive detectors are arranged into four quadrants.  
   
   
       98 . The method of  claim 97  wherein the energy dispersive detectors are separated by a plurality of vanes.  
   
   
       99 . An apparatus for identifying an object concealed within a container, comprising: 
 a first stage inspection system having at least two X-ray projection systems to generate a first set of data;    a plurality of processors in data communication with the first stage inspection system wherein the processors process said first set of data to generate at least two images;    a processor executing an algorithm for selecting a region associated with each image;    a means for positioning an inspection region relative to the target region wherein the inspection region at least partially physically coincides with the target region; and    a second stage inspection system for generating the inspection region wherein the second stage inspection system produces a second set of data having an X-ray signature characteristic of the material in said inspection region.    
   
   
       100 . The apparatus of  claim 99  wherein the region associated with the images is selected based upon an X-ray image characteristic.  
   
   
       101 . The apparatus of  claim 100  wherein the X-ray image characteristic is at least one of mass, degree of attenuation, area, atomic number, size, shape, pattern, or context.  
   
   
       102 . An apparatus for identifying an object concealed within a container, comprising: 
 a first stage inspection system having at least two X-ray projection systems to generate a first set of data;    a plurality of processors in data communication with the first stage inspection system wherein the processors process said first set of data to generate at least two images;    a processor executing an algorithm for selecting a region associated with each image;    a means for positioning an inspection region relative to the target region wherein the inspection region at least partially physically coincides with the target region; and    a second stage inspection system for generating the inspection region wherein the second stage inspection system produces a second set of data having an X-ray signature characteristic of the material in said inspection region and comprises an array of transmission detectors.    
   
   
       103 . The apparatus of  claim 102  wherein the second stage inspection system further comprises an energy dispersive detector.  
   
   
       104 . The apparatus of  claim 103  wherein the energy dispersive detector is used to produce a signature of the material in the inspection region and the array of transmission detectors is used to produce data defining at least one of mass, degree of attenuation, area, average atomic number, of the material in a beampath.  
   
   
       105 . The apparatus of  claim 102  wherein the array of transmission detectors comprises high energy and low energy detectors.  
   
   
       106 . The apparatus of  claim 105  wherein a reference spectrum is determined by identifying a spectrum associated with data generated from both the high energy detectors and the low energy detectors.  
   
   
       107 . The apparatus of  claim 106  wherein the reference spectrum is used to correct a diffraction spectrum.  
   
   
       108 . The apparatus of  claim 106  wherein the reference spectrum is used to correct for beam hardening.  
   
   
       109 . An apparatus for identifying an object concealed within a container, comprising: 
 a first stage inspection system having a X-ray projection system to generate a first set of data;    a processor in data communication with the first stage inspection system wherein the processor processes said first set of data, said first set of data being indicative of a target region;    a second stage inspection system for generating an inspection region proximate to the target region wherein the second stage inspection system produces a second set of data; and    a processor capable of executing a neural network to process the second set of data to determine the existence of a threat.    
   
   
       110 . The apparatus of  claim 109  wherein the neural network operates as a back-propagation network having a plurality of nodes and wherein said nodes are organized in a series of successive layers, each layer comprising at least one node that receives inputs from nodes in a prior layer and transmits outputs to nodes in a subsequent layer.  
   
   
       111 . The apparatus of  claim 110  wherein nodes in a first layer are weighted in accordance with their distance from at least one node in a second layer.  
   
   
       112 . The apparatus of  claim 111  wherein the neural network is trained to determine the existence of the threat using a plurality of libraries.  
   
   
       113 . The apparatus of  claim 112  wherein the libraries are accessible via a network.  
   
   
       114 . The apparatus of  claim 113  the libraries comprise at least one of a threat library, a non-threat library, and a buffer library.